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site & Forum are moving to a new server and ISP. It need time due the large amount of data present in the lavteam servers.. So be patience....

Hi everyone This straightforward tool generates a stream order network from elevation data (DEM). The only input required is a DEM. As an open-source tool, it is accessible and easy to use. If you encounter any issues, feel free to contact me at [email protected]. Tested with ArcGIS Desktop 10.8.1😊 Let me know if you'd like further refinements Download Link To create a stream network and determine its order in ArcGIS starting with a Digital Elevation Model (DEM), follow these general steps: Step 1: Prepare the DEM Load your DEM into ArcGIS. Ensure the DEM is hydrologically correct, without any errors like sinks or pits. Use the Fill tool from the Spatial Analyst toolbox to fill these voids Step 2: Flow Direction Use the Flow Direction tool to compute the direction of water flow across the DEM surface. This creates a raster that assigns a flow direction to each cell Step 3: Flow Accumulation Apply the Flow Accumulation tool to calculate the amount of flow accumulated for each cell based on the flow direction raster Step 4: Stream Threshold Set a threshold value for the Flow Accumulation raster to define streams. The Con (conditional) tool can be used to extract cells that meet this threshold. This step essentially defines what qualifies as a stream Step 5: Stream Link Use the Stream Link tool to assign unique identifiers to connected stream segments. Step 6: Stream Order Apply the Stream Order tool to calculate the hierarchical order of streams (e.g., Strahler or Shreve order). Step 7: Vectorization (Optional) Convert the raster stream network to a vector format using the Stream to Feature tool. This makes the streams easier to visualize and analyze. With these steps, you'll have a stream network derived from your DEM with ordered streams that can be used for further hydrological analysis.

Maxar Intelligence developed a visual-based navigation technology that enables aerial drones to operate without relying on GPS, the company announced March 25. The software, called Raptor, provides a terrain-based positioning system for drones in GPS-denied environments by leveraging detailed 3D models created from Maxar’s satellite imagery. Instead of using satellite signals, a drone equipped with Raptor compares its real-time camera feed with a pre-existing 3D terrain model to determine its position and orientation. Peter Wilczynski, chief product officer at Maxar Intelligence, explained that the Raptor software has three main components. One is installed directly on the drone, enabling real-time position determination. Another application georegisters the drone’s video feed with Maxar’s 3D terrain data. A separate laptop-based application works alongside drone controllers, allowing operators to extract precise ground coordinates from aerial video feeds. “This system was designed to plug in and be a proxy for GPS,” Wilczynski said. The 3D terrain data is regularly updated, and Maxar can task its satellites to refresh information for specific regions of interest based on customer needs, he said. source: SpaceNews

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